Additive BIO Fabrication: Impact, Opportunities and Challenges

Written by:

Prof. Gordon Wallace and Dr Stephen Beirne
Follow Gordon on Twitter: @gordongwallace

ARC Centre of Excellence for Electromaterials Science (ACES)
Intelligent Polymer Research Institute, AIIM Facility, Innovation Campus
University of Wollongong, Wollongong, NSW 2522, Australia

First published in ATSE magazine (Academy of  Technological Science & Engineering)

In recent years we have outrun our ability to fabricate structures from the amazing materials that we can now create. While this can be said of many areas of materials research it is particularly so in the area of biomaterials. Here, we are often confronted with delicate compositions with nano- to microscopic features that will not survive the traditional (hammer and chisel) approach to fabrication. There is good reason why nature “grows” complex, highly functional structures. Such structures with functionality determined by the spatial distribution of composition with nanodimensional resolution can not be chiselled from a slab of material.

Additive fabrication (AdFab), often referred to as 3D Printing, involves layer-by-layer deposition and fusion of materials to create customised structures. The structure to be produced can be conceptualised, manipulated and defined within a growing array of modelling environments; from conventional parametric Computer-Aided Design (CAD) solutions such as Solidworks™ or ProE™, through to free-form animation toolsets such as Autodesk 3ds Max™, and even free web-based applications like Tinkercad™ (www.tinkercad.com). Once a design is completed, a file that describes the structures’ surface geometry is generated and a set of digitised instructions then drives the printer to create the required structure layer by layer.

The fabrication process can involve several deposition modes. In fused deposition modelling / extrusion printing, a molten build material is deposited and solidified on cooling.  For higher resolution structures (layer thicknesses as low as 16 µm), a fluid material precursor is ink-jetted onto a substrate and simultaneously transformed into a solid structure via a chemical reaction (UV induced polymerisation). Metal structures can be fabricated through a physical micron-scale welding process known as selective laser melting.

The Impact

The recent race to embrace AdFab has had significant wide-ranging impact on those of us involved in biomaterials and biodevices research. For example:-

In Wollongong, we have established Additive Biofabrication capabilities within a dedicated Processing and Devices Facility (Figure 1). Equipment housed here includes commercial additive fabrication systems like the Objet Connex 350™ and Relaizer SLM50™, commercial bio-fabrication systems such as the EnvisonTec Bioplotter™, and customised printing systems such as the KIMM SPS1000, a Reactive Ink-jet Printer and an Extrusion Printer. A more detailed description can be found at http://www.electromaterials.edu.au/equipment/index.html

Figure 1: AdBioFab at Innovation Campus – UOW

The ability to create customised 3D polymeric or metallic structures in the laboratory accelerates experimental design by enhancing the realisation of material components that facilitate experimentation. Additive fabrication provides an in-house capability to design and realise unique set ups in a minimal period of time.

One case in point was the development of an experimental procedure to electrically stimulate cells in vitro on organic conducting polymer surfaces (a study in the field of “Organic Bionics”[1]). Off-the-shelf chamber wells were removed from their original substrate and bonded to a conducting polymer coated gold Mylar substrate to act as a media reservoir. A custom platinum counter electrode mount was produced by additive fabrication (see Figure 2). The mount allows accurate placement of the platinum mesh electrodes in the media reservoir and ensures a repeatable electrode orientation. A proprietary bio-compatible material, Objet MED610™, was chosen as the build material. Production of these components by conventional machining would have been relatively expensive and would not have easily facilitated the small dimensional features of the component.

Batch production of biocompatible components using Objet MED610™ for use in biological experiments (Fig. 2.A)

Platinum mesh electrode mount as used to provide repeatable spacing between electrode surfaces during cell stimulation trials
(Fig. 2.B).

Another example of experimental tool production involved the development of a device to enable studies related to the alleviation of eye pressure arising from glaucoma; a study led by Prof. Michael Coote at the Centre for Eye Research Australia. Concept outline sketches were provided and translated into 3D CAD models. Graphical representations of the implant design allowed for revisions and modifications to be easily communicated and implemented before fabrication (Figure 3).

Batch production of an array of design permutations was achieved in a single build tray printing cycle. Design iterations were simply undertaken without any concern for re-tooling of the hardware.

Figure 3: Illustration depicting concept glaucoma implant as developed within Solidworks™ 2012 and highlighting external dimensions. Completed device as produced using Objet MED610™, after addition of 700 μm OD silicone tubing.

These examples illustrate what can be achieved with commercially available machinery and materials. In other aspects of our work within the ARC Centre of Excellence for Electromaterials Science (ACES), we are concerned with the fabrication of structures containing biopolymers, organic conductors and even living cells within new structures for bionics[1].

Existing commercially available equipment can not handle such materials. Consequently we have been involved with the Korean Institute of Machinery and Materials (KIMM) and the company M4T, who have supplied a customised Scaffold Plotting System (SPS1000™) that is capable of extrusion printing biopolymers; including synthetic biodegradables such as polycaprolactone, or naturally occurring biopolymers such as chitosan. Using this system, we have printed 3D scaffolds (Figure 4(a)). The lower feature size is limited to about 200 µm and is determined by the rheological properties of the bio-ink. Such structures have previously proven useful as scaffolds for tissue regeneration. More recently we have modified this extrusion printer to enable co-axial printing. This required the design and fabrication of a dual reservoir system and a co-axial print head (Figure 4(b)). These components were designed and fabricated in-house – the printhead itself was produced using a 3D metal printer – the era of printing printers is upon us!  Co-axial structures with an inner core diameter range of 200 to 500 µm and an outer core of 600 to 1200 µm diameter were produced. This customised co-axial printing system has already proven useful for the creation of alginate / polycaprolactone co-axial 3D structures and even the creation of structures containing living cells[2].

4a: Porous polycaprolactone (PCL) structures produced through hot-melt extrusion printing in an array of structure geometries based on geometric .stl data and user defined grid spacing parameters.

4b: A batch of co-axial extrusion tips, before final finishing and polishing, produced in Stainless Steel 316L with a Realizer SLM50™ operating with layer slice thickness of 25μm

Using a commercially available ink-jet printer from Dimatix™ and a customised ink using organic conducting polymer nano-particles, we have printed features as small as 20 µm that have been used as bionic guidance tracks to control the direction of nerve growth[3]. Another addition to our printing armoury is a custom built multi-head ink-jet printer that allows printing of multiple components to create new material structures during fabrication, so called reactive printing, wherein the individual components react to form a more mechanically robust structure. For example, this has been used to form biopolymer hydrogel structures that are ionically cross-linked during printing.

With minimal modification, we have also found these print heads to be useful in allowing for the effective delivery of living cells during the printing process; delivering both nerve and muscle cells to create unique biofunctional structures. The cells are maintained using a biopolymer suspension with optimised rheological properties that enable effective delivery through the ink-jet head. The formulation used is multi-purpose and multi-functional, in that it maintains the cells in a healthy state in suspension for many hours, protects cells during delivery and sustains cell viability after printing [4].

AdBioFab – Changing the way we teach, commercialise and do research

After a number of decades wherein advances in materials science have often been limited by our inability to fabricate effectively, we have now entered a new era. Biomaterials researchers have been empowered with the ability to fabricate customised structures using hardware that can be accommodated in most research laboratories at reasonable cost.

The convergence of advances in biomaterials, AdBioFab, Information technology, Nano technology and Bio technology is set to move us forward in biomedical science at an unprecedented rate. Our ability to convert data into knowledge and to effectively disseminate that knowledge has been outrun by our ability to create the primary data!

The knowledge dissemination gap continues to grow wider and this has implications for:

•  Schools and Universities: those responsible for skilling the next generation of researchers.
•  Regulatory authorities: who require information and an understanding of the implications of advances occurring on a number of technological fronts simultaneously.
•  The commercialisation sector: these advances are challenging traditional commercialisation models that are based on mass-manufacturing / cost reduction / sales targets. With additive biofabrication, localised manufacture using exotic materials will deliver the most effective solutions.
•  The community: social acceptance of advances in the medical sector is obviously critical to success. We must develop innovative approaches to present understandable chunks of knowledge.

Now we in materials science can be bold, even audacious. We can develop materials not amenable to current processing and fabrication approaches with the knowledge that we can print-printers; creating the fabrication machinery of the future in tandem with breakthroughs in materials science!

Advances in AdBioFab will have a staggering impact because it not only accelerates the thought-to-thing process, delivering practical solutions sooner, but it also empowers us to make unprecedented fundamental advances. For example, the ability to arrange living cells in 3D within naturally occurring or synthetic biomaterial structures will give insights into environmental effects on cell behaviour – insights hitherto unavailable.

Acknowledgements

The establishment of Additive Biofabrication capabilities in Wollongong has been made possible through the support of the Australian Federal Governments EIF program in providing a processing and devices fabrication facility. Equipment has been made available through EIF as well as the Australian National Fabrication Facility (ANFF) via the Australian Federal Governments NCRIS program. Personnel and personnel support has been provided through the NSW State Government Science Leveraging Fund and the ANFF.

References

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[1] Wallace, G.G., Moulton, S.E., Higgins, M.J., Kapsa, R.M.I. “Organic Bionics” Wiley-VCH Verlag & Co. KGaA, Boschstr. 12, 69469 Weinheim, Germany 2012.

[2] Cornock, R., Honours thesis, University of Wollongong 2012.

[3] Weng, B., Liu, X., Higgins, M.J., Shepherd, R., Wallace, G. “Fabrication and Characterization of Cytocompatible Polypyrrole Films Inkjet Printed from Nanoformulations Cytocompatible, Inkjet-Printed Polypyrrole Films” Small 2011, 7 (24), 3434-3438.

[4] Ferris, C.J., Gilmore, K.J., Beirne, S., McCallum, D., Wallace, G.G., in het Panhuis, M. “Bio-ink for on-demand printing of living cells” Biomaterials Science, 2013, 1, 224-230.

All washed up: have surf megabrands forgotten their roots?

By Andrew Warren, Post-Doctoral Researcher at University of Wollongong and Chris Gibson, Professor of Human Geography at University of Wollongong.

Australia’s surf megabrands — once thriving cultural icons — are now facing a changing tide of fortunes.

 

Yesterday’s announcement that iconic brand Rip Curl plans to sell-up raises the question: just what has happened to Australia’s iconic surf brands?

It has been well publicised that the big three surf labels – Rip Curl, Quiksilver and Billabong – have experienced shrinking sales and expanding debts. Suburban consumers have turned away from expensive surf-branded apparel. Coupled with the rise of online shopping, doubts are growing about the future viability of corporatised surf brands.

Raw economics certainly matters to the surf industry. The big three have been hit hard by recession in the United States and Europe, where they have concentrated most of their retail investment. Their timing was terrible. Just before the GFC, Quiksilver and Billabong both expanded their business operations. Billabong bought up a substantial number of surf retail outlets. Quiksilver acquired, and has since had to sell, a series of non-surf leisure brands – including Rossignol skis and Cleveland Golf equipment. Expansion added huge debts, which became difficult to finance when retail returns evaporated.

A subcultural industry

We think the problems facing the big three can also be explained through understanding surfing subculture. From informal beginnings shaping boards in backyard workshops and tool sheds, the selling of the surf remains strongly influenced by subcultural values and fashion cycles within the surfing scene.

In our new book on the surf industry, to be published next year by University of Hawaii Press, we make the point that, like music, it is a subcultural industry defined by a tension between “major” corporate labels and smaller “independents”. Independent labels have more credibility because they are considered closer to the grassroots of surfing culture. They are often based in specific surf cities and regions – southern California, the Gold Coast, north shore O’ahu – where surf subcultures are strong.

When brands grow and expand, they take on the character of corporate enterprises. The listing of Quiksilver on the NYSE in 1998 and Billabong on the ASX in 2000 signalled abrupt changes to the existing structure of the surf industry. Rightly or wrongly, many surfers felt that profitability and capital growth became more important than fulfilling surfer’s needs and desires. Surf companies have up-scaled production, acquired smaller brands, opened flagship retail stores and supplied stock to department stores. Quiksilver now supplies their surf-wear to department chain Macy’s in the United States and David Jones in Australia. Increasing market share is the goal, to pay shareholders dividends. Brand visibility to the masses is everything. But this undermines the claim to service local roots and the needs of every-day surfers.

Undermining credibility

The marketing of surfing’s cool image has allowed companies to sell the surf to a wider range of consumers. Despite its inland geography, in 2010 the US mid-west region was worth a remarkable $457 million in surf retail sales. The trade-off is that selling surf-wear through department stores undermines scarcity and subcultural value. Brand credibility falters.

This is not new. In the 1960s surf, labels Ocean Pacific and Hang Ten successfully diversified from surfboards and board shorts into different types of surf and swimwear. Yet in the 1980s, when their products moved out of surf shops and into department stores, subcultural affiliation collapsed. The big three now appear to be heading in the same direction.

When scarcity value is lost, other independent labels fill the niche. They look much more authentic and responsive by comparison. Their surfboards, clothes and apparel are harder to find, raising scarcity value. Independent brands appear rooted in surfing cities and regions. Corporate surf firms, by contrast, appear placeless and “uncool”. In time, the “majors” swallow up newer, smaller “independents” (as happened with RVCA, Palmers, Dakine and Von Zipper), temporarily leveraging their street cred. But the cycle starts all over again.

Differences and divergences

While the big three surf brands clearly face hardship, it is wrong to assume that all three are the same, or are equally doomed. Quiksilver and Billabong are listed companies. Responsibilities to shareholders and investors will influence future business planning. Any restructuring of Billabong and Quiksilver, or recapturing of their subcultural cachet, is unlikely to involve winding back stock from department store shelves. The recent appointment of former Target CEO Launa Inman as head of Billabong confirms this.

Rip Curl, on the other hand, remains privately owned. Whether this grants more flexibility to maintain ways of doing business that retain credibility and profitability is moot. Nevertheless, Rip Curl maintains a stronger strategic focus on surf “hardwear”: wetsuits and surfboard retail. Despite a dramatic fall in the last 12 months, Rip Curl remains profitable.

Surfing industry, surfing subculture

Broader economic conditions have gutted the performance of Australia’s largest surf brands. But macroeconomic conditions do not explain the full story. Surfing is a subculture, not an anonymous market for run-of-the-mill consumer goods. Given Australia’s strong connection to surfing, demand for surf products and equipment will endure. Newer, edgier brands will emerge and compete for market share. Whether the big three Australian firms can adapt and maintain their connections to surfing subcultures will be interesting to watch. Beyond the shopping mall, the key to understanding surf capitalism is watching the unfurling logics of its subculture.

This article was originally published at The Conversation.
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Who’s hunting who? Misguided responses to shark attacks

By  Andrew Warren and Leah Gibbs, from the School of Earth & Environmental Sciences at University of Wollongong.

There is no evidence that hunting and killing sharks reduces attacks on humans. US Fish and Wildlife Service

The most recent fatal encounter between a shark and a surfer off the coast of Western Australia is a tragic loss of human life. It prompted a Western Australian government reaction to “hunt and kill” the individual animal responsible for the attack. But this is a misguided response, and it’s time we discussed better solutions.

An apparent increase in “shark attacks” has stirred up debates about appropriate longer-term responses, including the possibility of culling sharks to reduce the likelihood of human fatalities. Shark attacks in the past year have been reported amid claims that white shark populations are increasing. But there is a sharp absence of scientific evidence to support this assertion. Rather, increased reports of sightings may indicate change in shark behaviour.

Circulating around these debates is a highly charged public response to both the loss of human life and plans to kill or cull marine animals as a response. There is however, no clear rationale for killing or culling sharks; on this matter governments and the media have been quiet. The governance process that led to the decision to “hunt and kill” in Western Australia remains elusive.

Re-evaluating human behaviour

The conversation about sharks and humans needs to refocus on responses that do not involve killing or culling. Rather than looking at the behaviour of sharks in relation to attacks on humans, it is time to evaluate human behaviour in relation to sharks, and their natural environment.

“Chumming” the ocean to lure sharks close to boats for tourism or recreational fishing is one practice that warrants scrutiny. In Australia and South Africa, tourism industries are now well developed around cage diving and white sharks. Some have suggested that filling the water with blood and fish carcasses to attract sharks close to cages and boats helps them associate a potential meal with the presence of humans.

Scientific evidence is inconclusive. However, at the very least it appears that chumming may alter shark behaviour and movement along coastlines. In light of recent attacks these practices should be discussed.

We can also benefit from using the knowledge we have built up about sharks, both scientific and local knowledge. Accounts from marine biologists, surfers, fishermen and regular beach users hold that entering the water near schools of bait fish is a bad idea. Sharks are often seen chasing small fish schooled together near the surface.

Likewise, swimming near open river mouths (especially after heavy rainfalls), where sharks commonly feed is not recommended. According to accounts by many experienced surfers and fishermen, early morning and dusk are times in the day when the chances of encountering sharks are increased.

Technological interventions provide another set of behavioural responses. On the NSW south coast an aerial patrol is used each summer to spot sharks and warn nearby surfers and swimmers when a sighting occurs. Repellent technology that disturbs sharks’ electroreception organs – their “Ampullae of Lorenzini” – is also being developed. Several companies now sell small battery-powered devices that emit a continuous electrical current. When a shark comes within a few metres it experiences severe discomfort – something like a sharp headache. Testing has shown that the technology can be effective. Devices can be worn by surfers, divers or swimmers and deter sharks without causing long-term harm.

Ethics and philosophy of human – shark relations

Encounters between sharks and humans will continue to occur in Australian waters. Most Australians live near the coast and the ocean is a popular recreational space. When attacks do tragically occur we need to consider a set of deeper philosophical questions and alternative responses:

• What right do we have to approve the killing of an animal for inhabiting its natural environment?
• What might be a better response?

Researchers from numerous disciplines invest enormous effort into such questions. Within our discipline of geography, there is extensive debate about the cultures and politics of human interactions with “nature”. Many scholars are working towards finding new ways of living ethically in the world, ways that are based on co-existence, and that respond to the challenges of rapid environmental change.

Interestingly, these ideas are consistent with a good deal of public discussion in recent months about appropriate responses to shark attacks. Many commentators – including surfers – call for co-existence rather than killing.

Environmental governance

This brings us to the question: why are we killing these sharks? This is inherently a question about governance. How and why is it that the decision-making process leading to a “hunt and kill” strategy is invisible?

Citizens should be in no doubt about the process that leads to such decisions. When the animal in question is a top-predator and protected species, what are our ethical and political obligations, responsibilities and rights? Whose interests should be heard and heeded? We look forward to forthcoming discussions about the protected status of great white sharks, and hope that deliberations are public.

Milton Friedman once said that crises – actual or perceived – are solved by ideas that are “lying around” at the time. Space needs to be created to allow for a public discussion on the politics of nature and environmental management. We must find alternatives that offer humans a sense of security and safety without delivering death and destruction to another species.

Alternative responses to challenging encounters between humans and sharks are “lying around”. We should think less about killing and culling and more about informed scientific, philosophical and political responses that enable co-existence.

This article was originally published at The Conversation.
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Australia’s rich talk about saving the environment; the poor bear the burden of doing it

By Lesley Head, University of Wollongong

Public housing tenants struggling with their bills will well understand NSW Community Services Minister Goward’s concern over the rising costs of nails and pots of paint. According to the minister, the carbon tax will push the price of household maintenance up; this is the reasoning behind an increase in public housing rents. But what’s fair about the state government passing its own carbon tax costs on to those least able to afford it?

To make matters worse, Ms Goward also announced that the imminent carbon tax compensation payments from the federal government will be included as part of a tenant’s assessable income. The state government may just be trying to score cheap points off the feds. But we should all be concerned about the social justice implications of framing the debate in this way.

For a start, more of the electricity price hikes are coming from infrastructure costs than from the carbon tax. A particular bottleneck and driver of change is the summer peak demand for air-conditioning, which low income households are less likely to use. All households are feeling the impact of increased electricity prices, but the pinch is disproportionately tighter if you are poor.

The same goes for the carbon tax. There is no cost-free way to make the necessary transition to lower greenhouse gas emissions. But as a community we need to find fairer ways to share these costs.

We also need to share the work. If you are economically comfortable and well educated, and think you are already carrying an extra burden, think again. Research shows clearly that the poor are doing the heavy lifting on a range of sustainability issues.

Our survey research shows that households earning less than $250 per week are statistically more likely to undertake sustainable household practices. They switch off lights in unoccupied rooms and put on extra layers of clothing before turning up the heating. They are more likely to repair than replace clothing. They are less likely to use an air-conditioner in summer, and much more likely to save water by taking shorter showers.

Not all such households profess “green” attitudes or sensibilities. And the poorest households were most likely to be “uninterested” in climate change as an issue. Ethnographic research throws light on this apparent conundrum. Often they are influenced instead by generational or socioeconomic backgrounds of frugality and thrift. They hate waste, and have many creative ways to save and reuse materials and stuff.

In contrast, households earning over $1700 per week are over-represented in the group undertaking fewer sustainable practices. Affluent well-educated households are more likely to profess pro-environmental attitudes, but their high levels of consumption make practical sustainability more difficult for them. They are more likely to own two or more fridges, and plasma screen TVs. Baby boomers are the least likely to be sceptical about climate change, but the most likely to fly often.

We are used to thinking about this in an international context; for example, comparing per capita emissions between Australia (high) and China (low). We are less inclined to acknowledge that there are also substantial disparities between Australian households.

The poor – particularly the elderly – are also more vulnerable to the impacts of climate change. They suffer heat stress in summer, and have to make hard choices between heating and eating in winter.

Most of us know people with cupboards or garages full of things that “might come in handy”. They might be Grandma, or the old guy next door. They are not all poor, and I am not suggesting we should celebrate their poverty. Rather, these unheralded vernacular practices – honed in diverse socioeconomic, generational and ethnic circumstances – provide cultural resources that we should acknowledge and draw on. We should celebrate their contribution towards helping us think about how to do things differently.

There are no easy answers here, but a double whammy for public housing tenants is surely not one of them. If the state government decreases tenant resilience by passing on the increased costs, they will end up paying more elsewhere, for example in the health budget.

We are all in this together, and need to find ways to share both the costs and the work of responding to climate change. We certainly should not be putting extra costs on that segment of the community who are already doing more than their share of the work.

Lesley Head receives funding from the Australian Research Council.

This article was originally published at The Conversation.
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Railways in Australia: Federation Unfulfilled

Each year, the Henry Parkes Foundation arranges for an oration to commemorate a definitive speech made by Sir Henry Parkes in October 1889 at Tenterfield, NSW. This speech gave real direction to Federation of the Australian colonies. The 2011 Henry Parkes oration was on the topic of railways and a brief summary (from the Summer 2012 edition of Track and Signal magazine) follows. The 2011 and earlier orations may be viewed at  http://www.parkesfoundation.org.au

Professor Philip Laird

By Philip Laird  – University of Wollongong

In his 1889 speech, Parkes had a clear vision of an Australian Federation that included an efficient rail system to increase both the nation’s defence capability and its prosperity.

If Sir Henry were to return today to Australia, he would be impressed with advances in railway engineering along with some world class operations. However, he would be greatly disappointed and quite angry at the substandard nature of rail in New South Wales. He would also demand to know why, 110 years after Federation, the nation’s railway gauges had not been standardised; and, why successive federal governments have failed to give Australia a fit for purpose rail system.

As a result of decisions taken at the 1897 Australasian Federal Convention in Adelaide, it was agreed that the powers of the Federal Parliament would include post and telegraphs offices along with defence and customs.  However, the control of the railways, except for defence purposes, was to remain with the States.

Over time, this decision not to transfer railways to the Commonwealth has proven to impose additional costs to Australia. Had railways been a Federal responsibility, as they are in Canada and the United States, the following 12 benefits could well have been realised.

A geological excursion to the Shakey Isles and an account of the Christchurch Earthquake

Rock fall following the Christchurch 6.3 earthquake. Source http://blogs.agu.org/landslideblog/2011/02/23/on-the-causes-of-the-high-levels-of-loss-in-the-christchurch-earthquake/

Posted 28 February 2011

Last week 11 students and staff from the School of Earth & Environmnetal Sciences (SEES) returned from a geological fieldtrip to the South Island of New Zealand to investigate active tectonic processes including the fault rupture from the magnitude 7.0 earthquake in Christchurch last September. Little did we know that a second large earthquake (magnitude 6.3) would devastate much of Christchurch only 5 days after our return highlighting the unpredictability associated with seismic hazards. 

The fieldtrip was organised by two SEES PhD students, Steph Kermode and Nathan Jankowski, who head up the student social group – GROUNDSWELL and was supported by SEES staff Brian Jones and Solomon Buckman. The students included a mix of postgraduates and undergraduates from all levels. The purpose of the trip was to observe active tectonic and glacial processes that have sculpted the landscape in New Zealand that are not readily observable in the relatively stable Australian continent. The long-term aim is to run this fieldtrip each year as an intensive field-based summer subject in which students can get first hand experience of active geological processes including volcanoes, geothermal power stations, glaciers and faults associated with active mountain building.   

The landscapes and mountains of New Zealand are incredibly young with most of the relief having formed in only the last 5 million years. This is in stark contrast to the Australian continent that has not experienced any major mountain building activity for the past 200 million years and subsequently been eroded down to a vast, flat continent. Despite the contrast, Australia and New Zealand share a common geological origin as they were joined together 85 million years ago as a part of the supercontinent Gondwana. Between 85-45 million years ago New Zealand rifted away from Australia creating the Tasman Sea that now seperates the two continents. New Zealand is situated directly on the boundary between the Australian and Pacific plates making it a particularly active in terms of volcanic and seismic activity. In the North Island the Pacific Plate is moving to the east and subducting (sinking) beneath the North Island resulting in the development of an active volcanic arc and a deep sea trench to the east which extends all the way to Tonga. To the south subduction has flipped with the Australian Plate subducting beneath the South Island to form the Macquarie Ridge and Southern Alps. In between the North and South Islands is an intense zone of faulting where the New Zealand continent is being wrenched apart by the Alpine Fault. This is a major transform (strike-slip) plate boundary and has been active for the past 25 million years. The Alpine Fault consists of many subsiduary fault splays along its length. The big surprise with the Christchurch earthquakes has been the fact that Christchurch has not experienced large or regular earthquakes in historic times and that the fault line has not been identified  due to it being buried by thick sequences of river sediment that has been eroded off the Southern Alps. Christchurch is also quite a distance from the Alpine Fault which may have built a collectively false sense of security. New Zealand is referred to as the Shakey Isles for good reason. It sits on the Pacific Rim of fire and is subject to regular, intense seismic activity as the tectonic plates jostle and collide with each other.

It was clearly evident when we visited Christchurch that it was still rebuilding from the September 3, 2010 magnitude 7.0 earthquake that struck 45 km west of the city in the rural outskirts of Roleston. It is important to realize that the Richter scale used to measure the magnitude of earthquakes is a base-ten logarithmic scale so an earthquake measuring 5.0 has a shaking amplitude ten times that of an earthquake of magnitude 4.0. However, the total energy released is 33.3 times the amount for a difference of 1. Put simply a difference of 2 on the Richter scale results in about 1000 times the amount of total energy released. Most movement on faults is accommodated by large earthquakes. Unfortunately earthquakes remain difficult to predict in the short time-scales useful to people due to the numerous variables – build up of stress, time since last rupture, water saturation of the fault plane and most importantly the fact that earthquakes generally occur 10’s to 100’s km below the surface where we cannot make direct observations of the physical conditions. Geologists rely solely on geophysical and seismic data to interpret conditions and structures deep in the lithosphere.

We visited the fault rupture and although the roads had been repaired the 4 m offset of roads, fences, hedges and canals was clear to see as well as numerous cracks and compressional mounds along the fault trace. It was also evident that many of the locals weren’t happy with the attention they were getting from passers by like us who wanted to stop and view the fault. There was a real sense amongst Cantebrians that they were lucky to get away without any loss of life after the first earthquake. Unfortunately that was not the case with the recent earthquake in which the death toll has just passed 100 and there are still over 200 people missing.

The epicenter of the February 21, 2011 magnitude 6.3 earthquake was only 5 km from the centre of Christchurch with the epicenter centred on Lettelton.  Because of proximity to the epicenter and the shallow depth (5 km) of the hypocentre, ground shaking in Christchurch was much more severe for this latest earthquake than for the larger magnitude 7 event in September. Ground accelerations were unusually high for this event, probably due to the shallow depth of the earthquake hypocenter and the thick unconsolidated substrate of wet mud and sand that much of Christchurch is built on. Compared to solid rock, sands and muds have the effect of slowing and amplifying seismic waves as they travel through the earth resulting in greater shaking. Wet sediments are also prone to liquefaction when shaken which means they suddenly change from behaving as a solid during normal conditions to a liquid during an earthquake. During an earthquake liquid sand or mud can spew out of cracks in the ground and flow down roads and collect in depressions and drainage networks. Heavy buildings and structures will tend to sink and become unstable during liquefaction if they do not have adequately engineered foundations. Typically ground shaking is in the order of 25%g  for a magnitude 6.3 earthquake but the Christchurch earthquake produced shaking of up to 188%g. To put this in perspective, any shaking above 100%g is enough to overcome the acceleration of gravity and start throwing objects up in the air! Although New Zealand has a very strong and strictly enforced earthquake building code, this level of shaking resulted in severe and widespread damage. The Modified Mercalli Intensity scale (I-XII) is used to measure damage based on observations and interviews. Levels of IX to X were recorded around the epicenter which means intense to violent damage of well-built stuctures and damage or destruction of some well built wooden structures. Most houses are built of wood in New Zealand because it is much more flexible and resistant to earthquakes than brittle brick structures. Unfortunately, aftershocks can occur for many months after an event creating dangerous conditions in already weakened structures. The other aspect is that where stress is released by an earthquake it can result in increased stress along other faults segments resulting in an “unzipping” effect as stress in the crust is redistributed and comes to a new equilibrium. This appears to be the case with this second magnitude 6.3 earthquake following the magnitude 7.0 earthquake last year some 45 km further west.

Part of my research involves investigating evidence of ancient earthquakes (Paleoseismology) in areas of Australia that are prone to seismic activity and I have a PhD student – Chulantha Jayawardena, investigating active faults in the Adelaide region. Although Australia is relatively stable compared to New Zealand it is still affected by earthquakes as evident by the magnitude 5.6 Newcastle earthquake in 1989 and the magnitude 5.4 Adelaide earthquake in 1954. Earthquakes in Australia are referred to as intraplate earthquakes as they do not occur on plate boundaries and are much less understood and certainly less predictable in terms of their distribution. The danger with these intraplate earthquakes is that they may have long recurrence intervals of 100’s or 1000’s of years before the crustal stresses build up enough to rupture and generate an earthquake and they can strike areas that are underprepared for such events. We are investigating active faults along the margins of the Mount Lofty and Flinders ranges in South Australia by way of trenching, mapping and using ground penetrating radar to identify previous ruptures. Some of these faults have rupture lengths and offsets of single events that suggest magnitudes in the order of 5-7 on the richter scale. Part of our research involves dating these paleoseismic events by sampling the sediments that have accumulated adjacent to the fault rupture using luminescence dating techniques (OSL) to further constrain the timing of past earthquakes. Identifying hidden fault lines and constraining the timing of past seismic events is of fundamental importance in understanding how mountains such as the Flinders Ranges form in intraplate settings and of course it has important practical implications in terms of planning and implementing appropriate building codes in earthquake prone regions of Australia.

Earthquakes are a global hazard that knows no political boundaries. Earthquake response and rescue efforts are often globally assisted and require the expertise of many disciplines including engineers, geologists, planners, medics, police and emergency response personnel. Earthquake mitigation is an ongoing process from the initial identification of faults and historic seismic activity, through to developing appropriate building codes, to the rescue efforts when these hazards strike through to planning for the next event. The tectonic processes so evident in New Zealand provide an important modern-day analogue in terms of understanding how older continents like Australia have been shaped and formed in the past.

For further information please contact Dr. Solomon Buckman solomon@uow.edu.au in the School  of Earth & Environmental Sciences

The Queensland floods, climate change or poor planning?

Professor Gerald Nanson

A number of media commentators and numerous letters to the editors in major newspapers have suggested that the recent floods in Queensland are some sort of bellwether of global warming and Australia’s hazardous climatic future in a warming world. There is no doubt the globe has been warming over the past century or so, and it seems very likely that this is a function, at least in part, of our introduction of excessive Greenhouse gases to the atmosphere. But Australian weather is far too variable today, and indeed has been so for thousands of years, to enable any confident predictions to be made about the changing magnitude and frequency of extreme events. The last major flood on the Brisbane River was in 1974 which coincided in many places with the most extreme flood events continent-wide since European arrival. So while we have just two such truly ‘catastrophic’ flood events in our recorded history, it is very difficult to say anything scientifically sound about their changing magnitude and the likely frequency of their occurrence. Scientists sometimes use smaller events analysed statistically to predict the likely size and frequency of extreme events, but Australian climate is well known to move in cycles, several decades in length, which commonly result in clusters of decades producing very different conditions to those before and after. Indeed, our natural climate is something of a rollercoaster ride. When ‘old timers’ timers say that a particular flood is the largest they have ever seen in their area, it isn’t necessarily because climate is changing, it’s mostly because even ‘old timers’ don’t live for hundreds of years. Global movement of the ‘climate goalposts’ can be used as an excuse for poor urban regional planning. There is abundant evidence of extreme flood risk in many areas of Australia, including in Brisbane, and much of this evidence was collected before global warming was an additional significant variable to consider. The human cost of flooding in Australia is mostly the product of poor planning, not climate change.

Professor Gerald Nanson is from the UOW School of Earth and Environmental Sciences

 Read another short essay from Gerald :
“The floods of Queensland have raised important issues relating to how well Australia collects data that is vital for the accurate analysis of potential hazards, and how adequately our country understands and therefore is prepared to deal with our extreme environmental hazards.”  More at: http://media.uow.edu.au/news/UOW094233.html

Climate Change is Real, Believe Me

Dr Helen McGregor

As a climate scientist I am often asked if I believe in human-induced climate change. I find this a curious question: for me the science of human-induced climate change is not something one believes in but an obvious conclusion drawn from the data. But it got me thinking – where has this belief/non-belief idea come from and why is there so much confusion about climate science?

There is no doubt that climate is a complicated beast. There are multiple players – the main ones being the atmosphere, ocean, vegetation, and ice – all of which interact with each other on a variety of timescales from hours to decades to centuries and beyond. Trying to describe all the processes, and to put them in a climate model, is a tough gig. But it can and has been done. Our daily weather forecasts are based on models, and though not perfect, they’re often within a couple of degrees Celsius of the actual temperature. That’s quite an achievement when you think about it.

Importantly, the models reproduce the observed 20th Century warming. This means that at least at the global scale we do have a good handle on the climate complexity. But communicating this complexity to the public is no mean feat and scientists aren’t always the best at communicating their own science in a language that non-scientists can understand.

One of the difficulties in communicating climate science is the concept of “uncertainty”. With the vast number of processes in the climate system there are some that we understand better than others – uncertainty describes how well we know what we know. Climate scientists, having a good understanding of uncertainty, tend to downplay the state of knowledge and this can be taken by some as a reason to do nothing.

But there are many instances where we may not understand a process 100 per cent still act. For example, we know that a healthy diet and exercise reduces the risk of heart disease, yet the details of exactly which food and how much exercise are still the subject of research. Does this mean we should have an unhealthy diet and not exercise? Of course not. The same principle applies to reducing carbon dioxide (CO2) emissions. We know that there is a big problem and should get on with the process of dealing with it.

The concept of uncertainty and the complexity of climate science also do not sit comfortably with the demand from the media for short “sound bites”, a black and white statement, one view for and one view against. Uncertainty is the greyness around the black and white. The for and against may appear to give balance but it misrepresents the almost absolute consensus among climate scientists – 97-98 per cent consensus according to findings published this month in the USA Proceedings of the National Academy of Sciences – and provides a louder voice to those who disagree with the idea of human-induced climate change than they would otherwise deserve.

Throw into this mix various lobby groups and vested interests in maintaining the status quo and the concept of uncertainty can be exploited further to confuse the public. In responding to human-induced climate change we move through climate science into economics, politics and social sciences. Between all of this it seems to become easier to frame the debate as a question of belief or non-belief. The understanding of how the science is generated and its implications are lost, and somehow by non-believing the problem does not exist.

But the issue of human-induced climate change is clear and present, and among all the confusion there are some fundamentals that will not change, and some misconceptions that must be addressed:

• Carbon dioxide in the atmosphere traps heat and this causes the atmosphere, and the planet, to warm.
• The burning of fossil fuels has increased the level of CO2 in the atmosphere. This has been measured directly at places like Mauna Loa in Hawaii and by measuring bubbles of trapped air in ice cores. CO2 levels have increased from 280 parts per million (ppm) at around 1800 to 385 ppm in the past couple of years. As a result the planet is about 0.7 degrees Celsius warmer. This doesn’t sound like much but there are knock-on effects from the temperature increase. Ocean water has warmed, and water expands when it’s warmer, so sea levels have risen. The warming is not distributed evenly across the world because the poles have warmed the most, so sea ice is retreating and the ice sheets have started to melt. Sea ice is important – it’s like a giant mirror reflecting the sun’s heat and light back out into space. Without the sea ice that heat is absorbed by the ocean, further warming the planet.
• The atmosphere, winds and the like, redistribute CO2 across the planet in a matter of months so that even though the US and China are the biggest emitters of CO2, those countries do not feel the full force of their own emissions. Hence global warming is a global issue.
• Australia is part of the CO2 problem. I often hear the argument, including from politicians, that Australia only emits about 1.5 per cent of the global total of CO2. Quite so, however 95 per cent of countries emit less than 2 per cent of the global total. It is not possible for countries to do nothing – Australia must reduce its CO2 emissions. Period.

As I sit here in bustling New York City, with the gulf oil spill making headline news day in day out, I can’t help but be anxious that climate change issues have slid under the radar. Human-induced climate change is insidious. It is not an acute, headline-grabbing event but the consequences of climate change will have far greater and far reaching impacts. The science provides the clear evidence that human-induced climate change is occurring – the real uncertainty lies in our collective ability to do something about it.

*Dr Helen McGregor, School of Earth and Environmental Sciences, recently visited the Lamont-Doherty Earth Observatory, University of Columbia, New York. Dr McGregor is now teaching in the Faculty of Science’s Climate Change subject.